Enables ionotropic glutamate receptor binding activity. Involved in establishment of protein localization to postsynaptic membrane; positive regulation of neuromuscular synaptic transmission; and regulation of postsynaptic membrane organization. Located in neuromuscular junction. Human ortholog(s) of this gene implicated in congenital myasthenic syndrome 11 and fetal akinesia deformation sequence syndrome 2. Orthologous to human RAPSN (receptor associated protein of the synapse). [provided by Alliance of Genome Resources, Apr 2022]